Valve



Nov. 18, 1941. R. w, CLIFFORD VALVE Original Filed Nov. 3, 1939 Patented Nov. 18, 1941 UNITED STATES PATENT OFFICE VALVE Roger W. Clifford, Schenectady, N.Y., assignor to American Locomotive Company, New York, N. Y., a corporation of New York Original application November 3, 1939, Serial No. 302,654. Divided and this application July 19, 1940, Serial No. 346,296

2 Claims.

ating uid to a power cylinder gradually and lent type, where a rotary valve is employed, `the valve includes a valve element which is initially manually moved by the locomotive engineer through lever means in the cab, to effect, through ythe agency of fluid pressure, movement of the reverse gear piston to its desired setting. The moving piston, through mechanical means including a iloating lever, effects return movement of the valve element. The valve element, upon exhaust it therefrom gradually during initial now, and thereafter at a rapidly increasing rate until full port opening. is obtained, thereby producing a rapid smooth ow of fluid.

Referring to the drawing forming a part of this application, Figure 1 is a diagrammatic side elevation of a locomotive embodying the present invention; Fig. 2 isan enlarged front elevation, viewed from the side of the locomotive, of the reverse gear mechanism shown in Fig. l, the reach rods extending therefrom being broken away; Fig. 3 is a front view of the valve of the present invention with certain parts removed;

Fig. 4 is a section on thev line IV-IV of Fig. 3,

The power reverse gear mechanism, of which` the present invention is especially adapted as a part thereof, is similar to the mechanism described in my above mentioned copending application, employing a type of servo-motor, andv reference may-be had thereto for'a'fuller description of the parts not particularly important for a clear understanding of the present invention. The following description will therefore be brief except as to the particular structure involved in `the present invention. It will be understood that while the valve of the present invention has been described in connection with a power reverse gear mechanism, for which it is especially adapted, it may be used for various other purposes.

In power reverse gear mechanism-of the pres- Ibe rectified by the control valve. 25l

reaching its normal position, effects through the fluid pressure agency, arresting of the` piston movement at its `desired setting.

In some types of conventional reverse gear mechanisms, the piston is mechanicallyheld in set position against the disturbing Lforces of the distribution valve gear and 'against creeping caused by the loss in Vpiston area at vthe piston `rod side of the piston due tothe cross-sectional 'area of the piston rod. In other types, such as the-,instant case, the fluid in the cylinder is relied upon to hold the piston, and where the fluid is a gas, such as air or steam, the tendency' to creep `is aggravated and isa factor which' must Movement of the piston due to the above mentioned disturbances will move the valve element of the reverse gear valve which in turn will effect return ofthe piston to its desiredproper position The mechanism, besides reversing the Valve gear which reverses the direction of travel of the locomotive, also operates to adjustl the valve gear for different cut-oifs, that is to say the piston of the mechanism operates as a control for the valve gear. Nevertheless the mechanism is commonly termed "a power reversegear, and therefore, for convenience, is so termed in'the description, and in the claims'appended hereto.

The Apower reverse gear mechanism shown is an improved mechanism forming the `subject matter of my above-mentioned co-pendng application. However, the particular mechanism used is not important insofar as the present invention is concerned, and this mechanism is chosen for illustrative purposes only. The instant valve is adapted for use with conventional reverse l 3, a piston 4 disposed therein, a piston rod 5 extending from the piston through a cylinder head i 6 at the forward end of the cylinder, a crosshead .guide 1 secured to thehead 6, a crosshead 8 slidtending from near the centerof-the chest (cylin-" The rotary* der) to either end of the cylinder. valve I of the present invention is secured. on

stem projecting into the air chest, by a spline connection for rotation with the valve stem. The valve element contains a keystone-shaped chamber 50. The top and bottom edges of these keystone-shaped portsl and of the chamber 55 are arcs struck from `a common axis, indicated by the reference letter a, which axis coincides with the valve stem axis. The side edges of the keystone- ,shaped ports 45 and 41 are radial from this axis,

"as indicated by the dot and dash lines b. The

f' side edges 5I and 52 of the velement 49 which contop of the chest'at the centerpartthereof vby f means of bolts and studs (not shown),-orific`esy I5 being provided for this purpose. The valve is disposed over ports I 1 and lI 'lformed `in the chest,

which are they external parts ofthe passages I3 lever `is pivotallyconnected at its upper end tothe-forward end vof the' rod24 by a pivotpin 26,

andfaft-itslower-end `tothe lower end of an arm 321, depending 'from' the crosshead, by a lpivot p'in28. A reach rod I129`is'pivotedat its forward end by a pivot pinf'7to an intermediate portion or the ffloatinglever, land at its rear end is secured to an operating lever 31 disposed inthe locomotive cab 321j 1 Y The-Valve I5is,lf generally speaking, ofthe type climi-'r'fion-1y used in pow'erf reverse lgear mecha- 1 Anisrns,-bu't modied'in accordance with the presentinvention. It consists of ay valve body 33 and faV cup-shaped valve body lcap 34, which are sefro cured vtogethfer'by studs E35'.' Thevalve body conl tains av transverse'orifice 'in which yare disposed bushings 36'. The" valvev stem I9 is vrotatably mounted'in these bushings, projecting at its rear end'through the rear'faceof the valve body for 'receiving the arm-2U; and projecting at its other :end intothe space `31 provided between the valve The 'bOdY V35 includes ana-ir inlet passage 38,51Y aSa-m imei? PEVSSgQ'M; an exhaust passage 40' andair or' steam outlet passages 4I and 42. The valve operation is Ythe same whether air or steam fis employed and consequently, for simplicity, only the term"air will'be used in the following description. 'Each vofith'ese passagesis Aopen Aat one end"toftheexterior of thebody=33- and at the other end terminates' in af'por't in afvertic'al face 431 off theirbotiy-SBVA ir vthe sequence,"air inlet port exhaust po'rt'j46 'for'` passagelll; outlet port II'IY for passage 3412,and;steamr inletportv 48 forv passage '39,'. 'The outlet pa'ssagesf4'l and-42! communicate y frspe'ctivfelywith the passages I3 and' Mythe' ilet 'passage138lisfconn'ectedlwithv a` supply of air- "serving Vfor' drainage.

trol the admission of air to the ports and 41 areradialvfrom a point c below the axis, as indicated bythe dot kand dash lines d. When the element is in normal position as shown in Fig. 5,

,the forward edge 52 crosses the forward side edge '53 ofstheport 41 to partly open the same, providing-a lead, later to be mentioned, but the rear edge5I does not cross the rear side edge 54' of port 45 but is rearward thereof, providinga lap. The :sideedges 55 and-56` of .the Vchamber5ll, .which control the' exhaust offair throughthe :port 46, Vare radial fromafpointfe above .this axisu, as indicated by the dot and dash lines f, so'lthat theedges .-55 and :56- crossl they adjacent edges 51 and 58=respectively ofthe port 45or 41 when the valveis moved one way orthe other from'norxnal position. Obviously =when `edges:initially cross there will be partiallport, opening. The purpose of this constructiomwhi'chis the' novel feature of the instant Valve, willlater/more fully appear.

The'fvalve ,body cap 34f'contansga recess 59 l'iavingan axis coinciding with thenaxis a. In the recess' 55'is ldisposerlthe stem ofy a valve follower 60, which follower bears against the elementv 49.

The element 49' and follower 6B v.are housedin the cup of tlie'capl;vv .Alcoil yspringI'Ljfis disposedn'the recess :553' between :the cutery end of the stem andthe. end' wa'lliof the recess opposite thereto: "I'he spring. exertsy a pressure. forcing .the followerr against the 'valve 'element vandthe valve element vagainst `the face A43. Threaded `orifices-62 are providedin the top and'bottomaof the rcap'll.l Both are ordinarily closedy with Vplugs (not shown) ,the upper :orice serving as an VVairadmission"porty in' place of the air inlet passage 38 when f desired, Iand 'A dowel '63 is'mounted -in-the'rocker arm- 20k v.and projects `forwardlyA into fa -recess- 54 -formed Tinv the adjacent `portion ofthe valve body. This dowel limits th'emovement offv the valve Velement which is initially moved -by-v Ithe lever 3l, thereby preventing' improper Vopening sof the ports =45,

The operation ofY ythereverse "gear mechanism' 'is as follows:

. 'Ihe Anormal position of; :the valve element is the position the valve element assumes when the I pistonbecomes balanced and is dependent upon 'such factors as the pistonfrod .diameter van'drthe load (piston-moving forces) imposed'bythejdis- --tri'bution valveigear'upon'the piston'. -Tliat is to say, .the'sourcefai pressure` onthe piston is afunder pressure '(notshown) the exhaust passage 40 opens to the atmosphere; and the steam pas'- 'sage3iseitherclosedw'ith a plug Vor connected `Tw'itlra Astean'rsupply (not shown) asianalternativefzactu'ating medium, when y desired, =all in the fusualrmannei.

,The passa'ges `.are 'all Vcylindrical inv `shape :but

itheiportsf-l, 46 and 41 farel approximatelyA keyfstonerinishape; They are reveredV by .fafvalvee1e- `1r1fent"49y which is rsecured Ifon "the endtof `the:vali/Te --fected"in`its actionby the loss'n' piston area due yto the'piston -vrod'and by "forcesexerted onthe piston'fby the'weigh't of the valve gearjmechanism. Thustlie piston'm'oves, in the present case, forwardlav'certain extent dependent upon these `factors, 'swinging the valve element out of rcen'tral po'sition'intol its" normal position, lat

`which position, for compensation, the port 41 is slightly open closed. Y

When theA lever=3l `is'in ajixed position for a as aforesaid and' the port 45 is the :lower ori'ce certain steam valve cut-oil and the locomotive is in motion, the valve element 49 is in normal position as shown in Fig. 5, latwhich time its forward edge 52 crosses the adjacent edge 53 of the port 41, leaving the aforementioned slight opening or lead, indicated by the numeral 65. Air escapes from the chest 31 through thisopening 65 into the passage 42 from which it goes to the forward part of the cylinder and maintains a pressure on the forward side of the piston suflicient to compensate for the aforesaid factors to effect balancing of the piston, port 45 being closed. 'I'his balancing is maintained during running of the engine at various valve settings or reestablished if disturbed, as has already been described, the ports 45 and 41 being suitably controlled by the valve element to accomplish this.

Movement of the operating lever 3| operates the reverse gear in the usual manner and only a brief description thereof is deemed necessary. If the reverse lever is moved forward, the floating lever 25 is moved forward, about the axis of the pin 28 as a fulcrum, which rotates the valve element 49 clockwise, uncovering the port 45 gradually as is shown in Fig. 7, wherein is shown a port initial opening 66,' and admitting air to the rear end of the cylinder. The piston 4 is therefore moved forward, the air at the forward side of the piston passing through passage 42 and port 41, which is then in communication with chamber 50, and out through the exhaust port 46 and passage 40 to the atmosphere. The forward edge 56 crosses the inner edge 58 of the port 41 gradually in a manner similar to the crossing of the outer edge of the port 45 by the rear edge I of the element 49 and therefore exhausts the forward end of the cylinder gradually. Forward movement of the piston moves the crosshead 8 and reach rod 9 forward which in turn adjusts the valve gear of the locomotive. As the crosshead moves forward it moves the lower end of the floating lever 25 forward. The lever 25 fulcrums about the axisv of the pin 30, the upper end therefore moving rearward, rotating the valve element 49 in a counter-clockwise direction and returning it to normal position. With the valve element in normal position, the total pressure is equalized on either side of the piston and the piston held in whatever positionr it may be in.

It will be understood that, similar to usual practice, in due course of operation the lever 3| will have reached its position for the desired cut-oli' setting and the engineer will then lock it in this position, thereby fixing the fulcrum pin 30.

Movement of the reverse lever in the opposite direction results in a similar but reverse cycle of operations.

If the edges 5| and 52 of the valve element 49 had been made radial of the axis a, openings serving for the same purpose as the openings 65 and 66, would have been provided in a conventional manner, but they would have extended for the full length of the sides of the ports 45 and 41. It has been found that, considering the opening of a closed port, such a port opening allows an undesirable sudden and excessive amount of air to enter the cylinder whenever the valve element moves from normal position. With the valve element in normal position very frequently the piston creeps enough to effect these port openings. The aforesaid conventional sudden excessive port opening is avoided in the present instance by disposing the control edges piston rod side of the cylinder.

'rapidlyincreases the edge 55 or 56 crossing, as

aforesaid, either the edge 51 or 58 of the port 45 or 41. Whereas the edges 5I and 52-aredrawn from a point below the axis a, the edges 55 and 56 are drawn `from a point above the axis a so that Athe lfirst exhaust opening provided by the crossing edges will be, similar to the first admission-opening, at the upper part ofthe port.

The aforegoing description hasbeen of a power l reverse gear mechanism wherein the unbalance of pressure on either sideof the piston has 'been taken care of by the valve element lapping, considering only the flow of air to the cylinder, one admission port and providing a lead at the other admission port, namely the port leading to the The crossing edges providing opening 65 adapt the instant valve I5 to particularly provide for this unbalance as the lead provided for by opening 65 can be made very small, being for just a portion of the edge 53. i

The instant valve, however, is also adapted for use in a mechanism wherein other means are vprovided to take care of the unbalance of piston pressures produced by certain causes, as for instance in the mechanism o f my co-pending application, filedJune 25, `1940, Serial No. 342,212, wherein a pressure-reducing valve is employed to equalize the totalpressures on opposite sides of the piston. f

The edges 54, 51, 58 and 53 of the-two ports 45 and 41 all diverge valong lines extending from a common point on the medial line between the two ports and 41, indicated by the dot and dash line :t in Fig. 5, and preferably from the valvestem axis a through which themedial line passes. The edges 5| and 52 of the valve element 49 diverge along lines from a common point c, and the edges and 56 of the valve element diverge along lines froml a common point e. The edges 5| and 55 dei-lne therebetween a flat blanking out face for the port 45, and likewise the edges 52 and 56 define therebetween a flat blanking out face for the port 41. The ports 45'and 41 and the blanking out faces, due to their respective converging side edges, are conveniently termed as being of keystone shape, this being a common shape of a keystone. The points e and c are preferably on the medial line between the two blanking out faces which line passes through the fixed point a. This medial line is not shown as it would be almost coincident with the medial line .'r, in the position of the valve element 49'as shown in Fig. 5. The valve element is preferably but not necessarily slightly rotated in Fig. 5, to provide a lead which throws the medial line for the blanking out faces slightly to the left of the medial line Obviously this medial line for the blanking out faces will travel with the valve element 49 as it is being rotated.

While there has hereinbefore been described an approved embodiment of this invention, it will be understood that many and various changes and modifications in form, arrangement of parts and details of construction thereof may be made without departing from the spirit of the inven- .tion amd'zthatgall. suchchanges and modifications as fall @within ther` scopefof athe appendedzclaims are contemplated: asfazpar-tof invention..

-cured'byLetters Patent is:

' The, invention .claimed-'rand-- .desiredy to be? .se-

2 1." The combination of a'rpowercylinder ;'-la}iiuid controlled pistonfslidable' :in said cylinder; ga control valve for `said piston comprisingfa'casing vproviding a Yfluid chamber, va shaft y mountedl in Vsaid casing; anda valve element mountedon said shaft-withinsaid chamber; and means vfor swingingy saidelement aboutvthevaxis ofi said shaft,said casing 'havingfa port kfor'continuoussupply of "fluid to saidchamber, and a fixed flat valveseat forming a wall vof'said chamber, lsaid' seat having la cylinder exhaust por-t and tWokeystone-Shaped ports, one .at eachfsideof Said exhaust port and spaced therefrom, said two ports communicating respectively with? opposite 'ends -of said' cylinder forselectivepassagelofdiiuid therethrough to said cylinder endsfrom' said' chamber; and`Y from vsaid cylinder ends' to said exhaust port; saidtwo ports having straight sides divergingalong lines all extending 'from acommon center onthe medial line between saidtwo ports 'providing' control edges forfsaidftwo ports, said valve elementhaving two `keystone-shaped lflat port blanking-outfaces, said jblanking out faces slidafbly engaging said seat, for

faces providing control Yedges coactingjeach'with an inner-edge of said two ports for controlling the exhaust to said exhaust port, saidblanking outifaces further having straight outer sides'di L `verging along lines extending from a com-mon center on said la'st mentioned medial `line and spacedfrom Vsaid firstv mentioned common center in a "direction away from said blanking outjfaces providing control edges coacting each with an "Outelfedge of said two portsA for controllingthe admission of iluidto said cylinder ends, all of said' blanking out face edges, when saidel'ement y whereby @gradually increasing. lV-shapedfl :initial lltlortii-opeislingr andgra'duaily :decreasing-:lveshaped .fnal'port closing will fbe effected.

l 2;*2 The 1combina`tionfof a :power cylinder; iauiiuid controlled piston vslidable insaidV cylinder.; `a; conn trolfI valve :'for said pistonfrcornprising a .casing is in central position and when swung; beingeach r at anl angle 'toits respective coactingport-edge i providing a fluidi chamber, als-haftV mounted in sai'dfcasing', and a valvefelement'imounted on said Ishaft' rwithinfsaid cham-ber ;J andmeans :for swing ing said element about the axis of saidfshalftsaid casing' having a portffor continuous supply .of "uid tosaid-chamber; and ai xedflatjvalveseat -formin'g a wall of':said".cl'1amber,y said. seat yhavinga; cylinder exhaustport and` twdkeystone-shaped :portsiz one at each'frside 'off said: exhaust :port `and vspaceditherefrom, said two ports communicating yrespectively' with .opposite 'lends ofv vsaid"fcyli1'1-der for selective passage of fluid therethrough tosaid cylinder ends, from'said-chamleerfand from -said cylinder :ends-tto said exhaust port, said two'ports :controledges for saidiI two ports,l said' valve lelement 'havingf two keystone-shaped at port blanking out faces, saidcblankingf out faces'zslid- 4ably -engaging'said seat,1-for b-lanking outsaid two ports, andzarecess opening .into'said'/exhaustlport` andextending at each side thereof tosaidbl'anking out faces'saidA iblanking. out yfaces having sstraight'inner 'sides idiverging `alongl lines extend- 'ingf fromrav common center' on themedi'alfline between said blanking out facesand spaced' from said axis in a 'directionttoward said'iblanlcing out faces providing control edges coacting each A`with .an inner edge o'fsaid two' po'rts'lfor controlling the 'exhaust to' said exhaustporu' lsaid blanking 'out'faces further having sifraight outer side'sediverging along lines *extending from a`V common center 'onffsa'idi medial line 'and spaced'. from said 'axisein* afdirectionaway/from said lalankingv out `faces providing kcontrolffedgesucoacting each with aan outer edge of vsaid two'ports' for` controlling the admission of fluid Lto' said cylinder? ends,.all of i j saidblankingy outface edges, when' said element isin central positionand vwhen swung,` beingj each atanifangle toits res'pectivei'co-a'cting portv edge whereby gradually increasing -V-shaped'initi'al port; opening and gradually l"decreasing fV-.sh'aped ''nal portclosingfwill be effected.

ROGER W. cniifeoisn).

Lhaving straight sidesdiverging.I alongl radial .lines l all extending from. Said '-axis,` providing `radial 

